JP2003507979A - Parallel core network for GSM / UMTS - Google Patents

Abstract

(57) Abstract: A location area connected to at least two core networks having the same function by a radio access network, wherein the radio access network transmits a packet from one of the at least two core networks from each terminal in the location area. A packet switched network architecture for switching to is disclosed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION

The present invention relates to an improved network architecture for packet switched networks.

[0002]

BACKGROUND OF THE INVENTION

GSM (Global Sys), also called second-generation (2G) wireless coverage
tem for mobile communications) wireless coverage is extremely widespread today. UMTS (Universal System for Mobile), also called third generation (3G) wireless coverage
With the introduction of Telecommunication), UMTS radio coverage is expected to be limited to urban areas. Therefore, UMTS radio coverage only covers a part of the wider GSM radio coverage area. UMT
Even within the S coverage area, UMTS radio coverage cannot be expected to be continuous. For example, the frequency used for UMTS is higher than the frequency for GSM, and the frequency penetration into the building is not as good as GSM. As a result, small pockets (such as inside a building) that fall out of UMTS coverage occur within the entire UMTS coverage area. Therefore, only GSM radio coverage can be used in these pockets.

Dual-mode GSM and UMTS mobile terminals (mobile terminals are referred to as user equipment (UE) in UMTS) can communicate using either of two radio access systems. When a dual-mode mobile terminal communicating over a UMTS radio link goes out of UMTS coverage and moves into a GSM coverage only area,
Continuing to communicate over the GSM wireless link can be expected, but as a result the service is degraded. Similarly, GSM moving to an area with UMTS coverage
Dual mode mobile terminals within the radio coverage only area can expect to switch to the UMTS radio link to improve service.

Thus, as dual mode mobile terminals move within a radio access area, changes in the type of radio access can be expected as the available radio access systems change. As the mobile terminal moves between radio access areas, a routing area update is performed to inform the required supporting networks of the mobile station's new location within the routing area associated with a particular radio access type. Switching between two radio access systems involves additional signaling,
May cause a hang at the transition between two systems. The impact of the additional signaling and outages depends on the network architecture and the protocol chosen.

Further, when a mobile terminal operating in the 3G operation mode moves out of the 3G coverage area, as a result, the service is deteriorated when the communication with the 2G core network is established.

An object of the present invention is to provide an improved network architecture for packet switched networks.

[0007]

[Outline of the Invention]

According to the invention, the radio access network comprises a location area connected by the radio access network to at least two core networks having the same function, the radio access network transmitting packet transmissions from each terminal in the location area to one of the at least two core networks. It is possible to provide a packet switching network architecture that switches (selectively connects) to one.

The radio access network may switch the packet transmission from each terminal to one of at least two core networks depending on the capacity of each core network.

The core network may include MSCs including VLRs, and the capacity of each core network is determined by the capacity of the VLR.

According to the present invention, a method for allocating resources in a packet switched mobile network, wherein at least two core network resources are allocated to a location area and each mobile user in the location area is allocated one of the core network resources. A method of associating packet transmissions from mobile users within a location area with one of the associated core network resources may also be provided. The present invention will be exemplarily described below with reference to the accompanying drawings.

[0011]

[Description of preferred embodiments]

The present invention is described below with reference to specific non-limiting deployment examples of third generation (3G) mobile systems and second generation (2G) mobile systems. In the specific example, the 2G system is a GSM / GPRS system and the 3G system is a UMTS system. However, the invention is not limited to such particular embodiments.

FIG. 1 illustrates the expected coverage provided by UMTS within the GSM radio access area. The shaded areas represent areas with GSM coverage only. The non-shaded areas represent areas of GSM and UMTS coverage. Therefore, Area 2 as a whole is provided with GSM coverage. Smaller area 4 within area 2
Is intended to provide UMTS coverage in addition to GSM coverage. However, since the pocket indicated by reference numeral 6 exists in the UMTS coverage area 4, only GSM coverage is provided in the pocket 6.

The proposed network architecture supporting the radio coverage shown in FIG. 1 is shown in FIG. GSM wireless access area and UMTS wireless access area
Different SGSN (serving GPRS support node)
It is considered as an independent system with separate location areas served by different mobile switching centers (MSCs). The SGSN provides a support node for each wireless system to support packet switched communication.

Referring to FIG. 2, the GSM radio access area is defined by a first location area 200, designated LA1, and the UMTS radio access area is LA2.
It is defined by the second location area 202 indicated by. The second location area actually coincides with the first location area as shown in FIG.

The first location area LA1 is associated with the GSM / GPRS BSS 204 and provides the GSM / GPRS radio access system with a radio access network. The BSS 204 is connected to the 2G core network 214 via the A interface 206 and the Gb interface 208. The second location area LA2 is associated with the UTRAN 210 and provides a radio access network for the UMTS radio access system. The UTRAN 210 is connected to the 3G core network 212 via the Iu interface 216 and the interface 218.

The 2G core network includes a 2G MSC 220, an integrated 2G visitor location register (VLR) 222, and a 2G SGSN 224. The 2G MSC is connected to the BSS 204 via the A interface 206. 2G SGS
N is connected to the BSS 204 via the Gb interface 208. MSC
220 is connected to its integrated 2G VLR via Map B interface 234.

The 3G core network includes a 3G MSC 226, an integrated 3G VLR 228,
3G SGSN 230. The 3G MSC 226 has an Iu interface 21
6 to the UTRAN 210. The 3G SGSN 230 is connected to the UTRAN 210 via an interface 218. 3G MSC22
6 is connected to the integrated 3G VLR 228 via the map B interface 232.

Each of the 2G and 3G core networks 214 and 212 of course also include other functional blocks. However, those functions are not shown in FIG. 2 as they are not relevant to the embodiments of the present invention and are apparent to those skilled in the art.

As can be seen from FIG. 1, the location area LA2 is actually part of the same geographical area as the location area LA1. If the mobile terminal is in the location area LA2, it will also be in the location area LA1. However, from the perspective of network architecture, location area 2 is treated as an area different from location area 1.

As the mobile station moves within the location area LA2, it enters and leaves the 3G coverage indicated by the pocket in FIG. In the network architecture of FIG. 2, a routing area update has to be performed every time the mobile terminal enters or leaves the 3G coverage in the area LA2, and when the 3G coverage is lost, the dual mode mobile terminal is It must continue in 2G mode, resulting in poor service.

One drawback to this is that 2G MSCs are implemented using 64 kbit / s technology, while 3G MSCs support much higher bit rates. When a mobile terminal with 3G capabilities has to switch from a 3G radio access network to a 2G radio access network, service is consequently degraded. Extending the infrastructure of the 2G core network to replace existing MSCs with higher specification versions is of course infeasible.

Therefore, it is necessary to provide a new MSC and integrated VLR in the 3G core network to support the 3G function of the mobile terminal. In short, the network architecture of FIG. 2 does not allow the full capacity of the radio access network to support mobile terminals with 3G capabilities.

A proposed new network architecture to provide improved utilization of advanced capabilities of 3G mobile terminals using existing 2G infrastructure is shown in FIG.
Is shown in. In FIG. 3, the same reference numerals as in FIG. 2 are used to identify elements corresponding to those shown in FIG.

In the network architecture of FIG. 3, the two separate location areas of FIG. 2 are “superposed” to form a common location area. Referring to FIG. 3, the common location area is labeled LA3 and is indicated by reference numeral 300. The location area LA2 corresponding to the 3G coverage area is also separately defined. Although the common location area LA3 is composed of 2G cells, mobile terminals in these cells with 3G capabilities depending on the network architecture may connect to a core network with 3G capabilities, as will be described in more detail below. it can.

The location area LA2 is composed of 3G cells as shown in FIG. 2, and a mobile terminal in the location area LA2 having a 3G function is connected to the 3G core network 212 via the UTRAN 210 radio access network as before. to enable.

The 2G BSS 204 of FIG. 2 has been modified in the embodiment of FIG. 3, and therefore the 2G BSS of FIG. 3 is designated by reference numeral 302. The 2G BSS 302 connects the 2G BSS 302 to the 3G MSC in the 3G core network A ′.
With an additional A interface labeled as 306. Two
The G BSS 302 also replaces the 2G BSS 302 with the 3G in the 3G core network.
Additional Gb labeled Gb 'labeled SGb to connect to SGSN
It has an interface.

According to the new network architecture of FIG. 3, the BSS 302 directs packet transmissions from mobiles in the combined location area LA3 300 to the 2G core network or the 3G core network. Similarly, in the opposite direction BSS30
2 directs packet transmissions to mobile terminals within the location area LA3 coupled from the 2G or 3G core network.

According to the implementation of the network architecture shown in FIG. 3, the radio access network including the BSS 302 switches the packet transmission from the combined location area to either one of the 2G core network or the 3G core network.

The radio access network including the BSS 302 can switch packet transmission from the mobile terminal to each one of the two core networks depending on several factors. For example, packet transmission may be the type of mobile terminal from which the packet was called, the capabilities of the mobile station from which the packet was called, or location area LA3.
It can be switched according to the 2G cell to which the mobile terminal is connected.

Although a radio access network with switching capability is a preferred implementation of the improved network architecture implementing a combined location area,
Other implementations are possible. For example, modify the 2G core network to include 3G functionality and add some control mechanism to select between 2G and 3G functionality.
The standard BSS 204 of FIG. 2 can be used in addition in the core network. This implementation is less preferred than the implementation shown in FIG. 3 as it requires changes to the 2G core network.

The technical feature enabling the “superimposition” of location areas LA1 and LA2 to be implemented is a single radio access connecting user terminals in two location areas to both 2G and 3G functions in the core network. Network (BSS302)
Is to provide.

Furthermore, the network architecture of FIG. 3 can be extended to a network architecture in which the location areas only partially overlap. That is, in the above 2G / 3G scenario, the 3G location area completely overlaps the 2G location area, and the 2G location area is larger than the 3G location area.
That is, the 3G location area exactly matches the 2G location area. However, the principle of "superimposition" of location areas may be extended to location areas that do not exhibit this characteristic.

Furthermore, the principle of “superimposition” of location areas can be extended to three or more location areas, and can be extended to three or more core networks. For example, in the future, the radio access network provided by BSS 302 may have the added capability of switching to a fourth generation (4G) core network.

Further, providing this network access architecture includes the BSS
Is not limited to use as a wireless access network. This technique is U
It can be easily applied to other radio access networks such as TRAN 210. U
The TRAN 210 may have a switching function in addition to the BSS 302, for example,
A 4G core network can be provided in addition to the 3G core network. U
The TRAN may also provide a switching function to switch between the 3G core network 212 and the 2G core network 214.

In the network architecture of FIG. 3, the BSS 302 has a 2G core network 214 and a 3G core network 212 provided in the location area LA2.
, But another 3G core network may be provided for this purpose.

Packet transmission is performed using the radio access network in the location area LA3.
The principle of switching from to one of two different core networks is even more generally applicable. With the introduction of 3G, mobile terminals will have dual capabilities, namely 3
It is likely to have the ability to operate as a 2G terminal instead of a 3G terminal when G wireless services are not available. By using the switchable radio access network, it is possible to switch the mobile terminal having 3G function in the 2G location area to the 3G core network. Thus, the mobile terminal having the 3G function can use a part of the 3G function even if the 3G function is connected to the 2G location area.

As described above, the principle of the radio access network capable of switching the packet transmission to the core network having different functions does not depend on the superposition of a large number of location areas, and more generally, a plurality of location areas can be used within a single location area. The present invention is applied to a mobile terminal having an operation mode of.

Referring again to FIG. 3, it can be seen that location area LA3 300, including location areas LA1 and LA2, is considered a single geographical area due to the superposition of two location areas. Therefore, the common location area LA3 can be identified using the single location area identifier. However, when the common location area identifier is used, the common location area 30
Mobile terminals in 0 would not be able to distinguish between each of the core networks with which communication is established.

According to another variant, the location area identifier for the common location area 300 comprises a core network identifier field that distinguishes between a 2G core network and a 3G core network.

Referring to FIGS. 4 (a) and 4 (b), there are shown implementations of location area identifiers transmitted by 2G and 3G core networks, respectively. Preferably, the location area identifier is a 16-bit sequence. According to this refinement, the core network identifier field that distinguishes the 2G core network from the 3G core network is the first bit of the 16-bit location area identifier. The first bit of this sequence is set to 0 or 1 to 2
Indicates G or 3G. That is, the core network from which the location area identifier originates sets this bit. The remaining 15 bits of the location identifier including the location area identifier (LAI) are the same. Therefore, the core network identifier field of the location area identifier is a pointer to the core network.

Referring to FIG. 4A, the location area identifier 402 generated by the 2G core network has the first bit 404 set to 0 and the location area identification LAI 406. Referring to FIG. 4B, the location area identifier 403 generated by the 3G core network has the first bit set to 1 and the location area identifier value LAI410.

Mobile terminals in location LA3 may have 2G or 3G capabilities. A mobile terminal with 3G capability can ignore bit 0 in the first bit position. These mobile stations preferably have dual mode capability so that all broadcast messages from the radio access network with the appropriate location area identifier are received by these terminals. This is because these terminals are 2G,
This is because all broadcast messages are received regardless of the 3G core network.
A mobile station having only 2G capability reads the first bit of the location area identifier and only the broadcast message with the bit set indicating that it originated within the 2G core network set.

Of course, if the 3G terminal in the common location area does not have the 2G capability, the bit reads the first bit of the location area identifier and the broadcast message is sent in the 3G core network. You need to make sure the bit is set as shown.

In the preferred embodiment, the location area identifier is a 16-bit sequence and the core network identifier field is 1 bit, although this may vary depending on the implementation. The location area identifier can be any number of bits and the core network identifier field can be any number of bits. In the alternative, the core network identifier may be determined by the location area identifier value being within a certain range.

Of course, if more than two core networks are accessible from the location area, the core network identifier can provide a suitable range of values.

The use of core network identifiers is also advantageous in the arrangements described above, where a single location area is accessible by several core networks of different functionality.

Another useful embodiment of the radio access network with switching function, already described with reference to the preferred embodiment of FIG. 3, will now be described with reference to FIG.
In FIG. 5, reference numerals similar to those in FIG. 2 are used to identify elements corresponding to those shown in FIG.

Referring to FIG. 5, the 2G network architecture of FIG.
2G core network 514 is introduced. The radio access network represented by BSS 302 in FIG. 2 has been replaced in the network architecture of FIG. 5 with a radio access network including BSS 500 having a switching function similar to that of BSS 302 described in further detail below.

The second 2G core network 514 includes a 2G MSC 520 and an integrated 2G V
LR522 and 2G SGSN524 are included. The 2G MSC 520 is connected to the BSS 500 via a second A interface 506 labeled A '. The 2G SGSN 524 is connected to the BSS 500 via a second Gb interface 508 labeled Gb '. The MSC 520 is connected to the integrated 2G VLR 522 via a Map B interface 534.

In this embodiment, the switching function of the BSS 500 is used to distribute the load to the two 2G core networks 214 and 514. This is particularly advantageous when the BSS 500 has a larger Erlang capacity than a single core network. Duplicating the core network allows the BSS 500 to operate near its capacity limit.

The techniques described above for including a core network identifier field in the location area identifier that distinguishes 2G and 3G functions within the network architecture of FIG. 3 are used within the network architecture of FIG. The networks can be distinguished. The mobile terminal in the location area LA1 can thus distinguish between the two core networks 214 and 514 using the first bit of the location area identifier and read out the broadcast message associated with the registered core network.

More generally, when a mobile terminal registers its presence in the location area LA1 with a random access request to the core network via the BSS 500, the BSS 500 sends this request to one of the two core networks 214 and 514.
Forward to one.

Upon confirmation of the random access request, the appropriate core network provides the mobile terminal with an identifier for use in all future packet transmissions. This identifier is included in every packet transmission by the mobile terminal and is used by the BSS 500 to direct the packet transmission to the appropriate core network.

The network architecture of FIG. 5 can be combined with the network architecture of FIG. 3, so that each of the 2G and 3G core networks can have a duplexed parallel network for load balancing.

[Brief description of drawings]

FIG. 1 illustrates the non-uniform nature of UMTS radio coverage within a GSM coverage area.

FIG. 2 is a diagram showing a network architecture for introducing a 3G service in an existing 2G environment of the present proposal.

FIG. 3 shows a modified network architecture for the introduction of 3G services in the proposed existing 2G environment.

4 (a) and (b) are diagrams showing location area identifiers that distinguish core networks serving a common location area.

FIG. 5 shows a network architecture supporting a single location area with the same functional parallel core network resources.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) H04Q 7/36 (72) Inventor Shiva Gunana Sundrum, Susa England Esd W 17 4 Eger London, Lines Road 93 F term (reference) 5K030 GA03 GA13 HA08 HC09 JL01 JT09 KA05 LB06 MD07 5K067 AA21 BB02 BB21 CC08 DD57 EE02 EE10 EE16 HH05 JJ64

Claims (4)

[Claims] 1. A radio access network comprising a location area connected to at least two core networks having the same function, the radio access network carrying packet transmission from each terminal in the location area to one of the at least two core networks. Switched network architecture to switch to. 2. The packet switched network architecture according to claim 1, wherein the radio access network switches the packet transmission from each terminal to one of at least two core networks depending on the capacity of each core network. 3. The packet switched network according to claim 1, wherein each core network includes an MSC including a VLR, and the capacity of each core network is determined by the capacity of the VLR. 4. A method for allocating resources in a packet switched mobile network, the method comprising allocating at least two core network resources in a location area, associating each mobile user in the location area with one of the core network resources. Switching the packet transmission from the mobile user in the location area to one of the associated core network resources.